Iproniazid (iproniazid phosphate, marketed under the names Marsilid®, Iprozid®, Ipronid®, Rivivol®, Propilniazida®) is a monamine oxidase inhibitor (MAOI) that was developed as the first anti-depressant. It was originally intended to treat tuberculosis when it was discovered that patients given iproniazid became "inappropriately happy," subsequently with further research iproniazid was marketed specifically for depression in 1958. It was later replaced by less hepatotoxic drugs.